package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IFollowService followService;
    @Resource
    private IUserService userService;
    @Override
    public Result queryBlogById(Long id) {
        // 查询 blog
        Blog blog = getById(id);
        if(blog==null){
            return Result.fail("博客不存在");
        }
        // 查询blog有关的用户
        queryBlogUser(blog);

        isBlogLiked(blog);

        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        // 获取登录用户
        //Long userId = UserHolder.getUser().getId();
        UserDTO user = UserHolder.getUser();
        // 应为这里首页会查询点赞 此时用户还未登录 空指针异常
        if(user == null){
            return;
        }
        Long userId = user.getId();
        // 判断当前用户是否已经点赞
        String key = "blog:like:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score!=null); // 是否点火过赞
        // 包装类有可能为空
        // 如果不存在
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
//        records.forEach(this::queryBlogUser);
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);

    }

    @Override
    public Result likeBlog(Long id) {
        // 获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 判断当前用户是否已经点赞
        String key = "blog:like:" + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        // 包装类有可能为空
        // 如果不存在
        if(score==null){
            // 未点赞可以点赞
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            // 数据库点赞 +1
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key, userId.toString(),System.currentTimeMillis());
                // 保存用户到 redis 集合中
            }
            // 保存用户到 redis 集合中
        }else {
            // 如果已经点赞 取消点赞
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            stringRedisTemplate.opsForSet().remove(key, userId.toString());
            // 数据库点赞 -1
            // 从 redis 集合中移出用户
        }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        String key = "blog:like:" + id;
        // 查询 top5 的点赞用户 zrange key 0 4
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        // 避免空指针异常
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 解析出其中的用户 id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        // 根据用户id查询用户信息
         // WHRER id IN (5,1) ORDER BY FIELD(id,5,1)
        String join = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id",ids)
                .last("ORDER BY FIELD(id,"+join+")").list().stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());

        // 返回

        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("获取笔记失败");
        }
        // 查询笔记作者的所有粉丝 便于推送

        List<Follow> follows =
                followService.query().eq(" follow_user_id", user.getId()).list();
        for(Follow follow:follows){
            Long userId = follow.getUserId();
            //推送
            String key = "feed:"+userId;
            stringRedisTemplate.opsForZSet()
                    .add(key,blog.getId().toString(),System.currentTimeMillis());
        }

        return Result.ok(blog.getId());
    }

    // 实现滚动分页查询
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 获取当前用户
        long userId = UserHolder.getUser().getId();
        // 查询收件箱  ZREVRANGE key Max Min LIMIT offset count
        String key = "feed:"+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 解析数据 blogId mineTime offset (时间戳）
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1; //offset
        for(ZSetOperations.TypedTuple<String> tuple:typedTuples){
            String blogId = tuple.getValue();  // 获取 id 字符串
            ids.add(Long.valueOf(blogId));
            long time = tuple.getScore().longValue();
            if (time == minTime){
                os++;
            }else{
                minTime = time;// 获取分数 即时间戳
                os = 1;
            }

        }
        // 根据id查询 blog
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id,"+StrUtil.join(",",ids)+")").list();
        for(Blog blog:blogs){
            // 查询 blog 有关的用户
            queryBlogUser(blog);
            // 查询 blog 是否被点赞
            isBlogLiked(blog);
        }

        // 封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);
        return Result.ok(scrollResult);

    }


}
